Sometimes Session databases can become corrupt and as a result, Capture One cannot open them and display your images in their last known state.
The advice below will help you to restore your photos to their adjusted state, but will replace the session database (.cosessiondb)
When you encounter a corrupt database, Capture One will usually notify you with the following message.
This does not mean that your images are corrupt - just the Session database. The steps below will help you to recover things such as adjustments, session favorites, and smart albums.
1. Re-open Capture One
Capture One will try to open the last used session or catalog. You can choose which document to use by doing the following:
Mac: Open the application whilst holding down the Option key (double-click the application from within the Applications folder, single-click if you are opening from the Dock)
Win: Double-click the shortcut or open Capture One from the Taskbar, then press + hold the Alt key before the application opens
Capture One will then show the following window:
Select New Session and save your new session with the same name but to a different location (for instance, in the Pictures folder)
2. Replace the corrupt/broken database
Navigate to the location where you saved your new session and copy the .cosessiondb file that can be found in the session folder with the same name.
Copy this file and paste it into the session folder of the original, corrupt session, in order to replace the database.
If you are asked whether you want to replace the file with the same name, then select 'Replace'
At this point, it is worth noting that you will lose your smart albums and session favorites, but those are easily recoverable if you are using a session template.
3. Recover session favorites and smart albums
If you are not using session templates, then you will need to manually re-build your session's smart albums and re-select your session favorites.
If you are using macOS, all you need to do is locate the folders used in your previous session's favorites and drag and drop these into the Session Favorites menu found in the Library tool.
When using Windows, you will need to click the + icon located in the Session Favorites in the Library tool and add your favorites one-by-one.
You should now find out that your session is fully replaced and that you are able to continue working with the same set of images, but with an updated database.